Manufacture of electric rare gas filled lamps



Aug. 1937. A. LEDERER MANUFACTURE OF ELECTRIC RARE GAS FILLED LAMPS Original Filed Dec. 20, 1930 INVENTOR Anton Lederer, %A

ATTORNEY Patented Aug. 24, 1937 FATE r FFHQE MANUFACTURE OF ELECTRIC BARE GAS FILLED LAMS Anton Lederer, Vienna, Austria; Catherine Danzer and General Conrad Randa, executors 02 said Anton Lederer, deceased, assignors to Ernest Anton Lederer, Glen Ridge, N. 3.

Application December 20, 1930, Serial No. 503,805

Renewed December 19, 1936. In Austria lDecember 28, 1929 9 Claims.

This invention relates to the manufacture of electric rare gas filled lamps.

In the manufacture of electric gas lamps or lighting tubes the rare gas filling of which is caused to glow by hot electrodes (such as for instance oxide cathodes) it is well known to introduce a getter substance (calcium, magnesium or the like) for the purpose of freeing the filling gas or gases from the last traces of im- 10 purities. This getter substance is located at some suitable place in the interior of the lamp and after completion of the lamp is vaporized by external heating, for instance by means of a high frequency current. The vapor after taking up the impurities of the gases condenses on the glass wall ,or other parts of the lamp after the latter has cooled down. If this getter deposit is formed at those parts of the glass wall through which the lamp is intended to emit light, the light emission would be considerably diminished and the object of the present invention is to provide for ensuring that the getter vapor shall deposit only at those parts of the lamp where it will not interfere with desired light emission at least to any considerable extent.

In the case of a lamp for example in which the bulb is of globular shape with a neck on the end of which a base is mounted for attaching the lamp to a lamp-holder, the main part of the light emission comes from the globe and it is not of importance if the getter deposit is formed in the neck of the lamp because little if any light is required to be emitted at this part of the lamp. In such a lamp therefore in accordance with the present invention, the vaporized getter is caused to condense on the neck of the lamp. This may be achieved by locating the getter substance at the start in the neck of the lamp. Furthermore, the neck may, after the vaporization of the getter, be maintained cooler than the remaining parts of the lamp and this assists in limiting the getter deposit to the neck.

In general, it may be said that it is advisable to cause the getter substance to evaporate and deposit either completely or as regards the greater part, away from the l'ght emitting parts of the lamp. This may be efiected by locating the getter at places of the lamp or its parts which are turned away from that portion of the lamp which is 5 intended to emit light, or by locating the getter in a separate receptacle which is in connection with the interior of the lamp. I In the case of high vacuum discharge tubes it is well known to take measures for preventing the formation of the getter deposit on certain (Cl. lid-122) parts of the discharge space or on certain of the interior parts (particularly the electrodes) of the tubes, and it has been proposed to locate the getter in a special separate chamber. In the case of high vacuum discharge tubes which act as rectifiers, or of radio tubes or the like, the light emission does not come into consideration, and consequently the prevention of the formation of the getter deposit at certain places has in the case of such discharge tubes an absolutely different purpose from that in the case of lamps with a rare gas filling for lighting purposes. Even in those cases in which in high vacuum discharge tubes the glass wall of the discharge space itself is to be kept free in order to interfere as little as possible with the radiation of heat from the discharge space to the exterior of the tube, this measure has an essentially different object from that' in the case of a lamp for lighting purposes because in the latter case it is essential not to interfere with the light emission, and interference with the radiation of heat is relatively unimportant.

A further consideration arises in connection with lamps of this kind intov which is introduced in additon to the rare gas filing a substance or substances giving ofi gases or vapors, particularly mercury by which the colour of the light of the rare gas filling of such lamps is influenced. For instance by the addition of small quantities of mercury vapor which itself would give a blue light at the discharge, the red or orange-red colour of the light of a neon or neon-helium filling is changed into a white or nearly white light. This mercury vapor can be produced in the interlor of the lighting tube from metallic mercury located therein or from mercury compounds; and it has been observed that the mercury vapor which is formed when the lamp is put in operation by the heating of the mercury introduced into the lamp is taken up by the getter deposit on the cooling down when the lamp is no longer in operation. Consequently there is no free metallic mercury in the lamp which might circulate freely or be thrown about, but the mercury is bound in the getter deposit. Whenever the lamp is put into operation and the gas filling is heated, the mercury evaporates from the getter deposit and partakes in the discharge; when the operation is stopped the mercury vapor is taken up again by the getter deposit for the reason that this deposit so to speak absorbs the mercury vapor, the more so when the deposit has been formed at a part of the lamp which remains cooler than the main portion of the discharge space. The mercury vapor has itself the tendency to deposit at the coolest part oi the lamp. Therefore, it is desirable that the mercury vapor shall not deposit at parts oi the glass wall through which the light emission ought to take place because the emission would be interfered with by the deposit of mercury. As the getter deposit attracts the mercury Vapor it is of ad== vantage to limit the getter deposit to places apart from the main portion of the discharge space so as to ensure the mercury vapor being outside the region of the main portion of the discharge space when the operation of the lamp is stopped.

This location of the getter deposit also prevents mercury vapor irom depositing on the electrodes. This would be disadvantageous, for, if the electrodes are stained by mercury the discharge and the light efiects would be unfavonr ably influenced. In such cases therefore, the getter has in addition to the well known action, the further purpose to prevent the formation of a deposit of mercury at" undesirable places in the lamp.

The acompanying drawing is a view, somewhat "diagrammatic, illustrating by way oi example only an electric lamp constructed in accordance with the invention. v

Referring to the drawing, i is a globe or portion of the lamp intended to emit light; 22 are the electrodes provided with. leading in wires 3 and supported on supports 6% in an ordinary manner. tending neck 5 in which is located a ring 6 carried on a. downwardly depending carrier 72 attached to one of the supports ii, ii is a small pocket attached or mounted on the ring E5.

In the manufacture of the lamp the getter is located on thering t and when vaporized deposits on the neck portion 5 of the lamp bulb so that i it does not interfere with the emission of light through the globe i.

The pocket d is used when in addition to the rare gas filling another gas such for example as mercury vapor, is provided. A compound of the gas or vapor, mercury for example, is placed in the pocket and evaporates when the lamp is heated to produce vaporization of the getter. When the lamp cools again the gas or vapor is absorbed by the getter deposit, but is given out .when the lamp is heated again.

No claim is made in this application for the construction of the light emitting portion of the lamp as shown in the upper part of the drawing, such being claimed in my prior applications, Ser. No. 468,884 filed July 18, 1930, and Ser. No. 497,025 filed November. 20, 19.30.

I claim:-

1. Steps in the production of an electric illuminating lamp having an envelope which con excitable to luminescence by cooperating electrodes at least one of which is adapted to be heated to electron emission temperature. which consist in introducing into the envelope a small quantity of mercury and also a vaporlzable substantially opaque getter which is absorptive to mercury when cool and is in a suficient quantity to be substantially completely absorbable by said getter, placing said getter in such a position that when vaporized it will deposit on a part of the envelope through which substantially no light is required to be transmitted, and subsequently vaporizing said getter and causing-it to deposit mainly on said part of the envelope and to air s orb the mercury.

The globe i has a downwardly extains a rare gas filling-and mercury vapor both.

accepts.

2. Steps in the production of an electric il lnminating lamp having an envelope which is bulb-shaped with a neck portion through which electrode leads enter and contains a rare gas filling' and mercury vapor both excitable to luminescenee by cooperating electrodes at least one of which is adapted to be heated to electron emis sion temperature, which consist in introducing into the necis portion of the envelope a vaporizable substantially opaque getter which is absorptive to mercury when cool, and subsequently vaporizing said getter and causing it to deposit substantially solely on said neck portion of the envelope.

3. Steps in the production of an electric il-= luminating lamp having an envelope which s bulb-shaped with a neck portion through which electrode leads enter and contains a rare gas filling and mercury vapor both excitable to lllil li nescence by cooperating electrodes at least one of which is adapted to be heated to electron emis sion temperature, which consist in introducing into the envelope a small quantity of mercury and fixing a sumcient quantity of magnesium in the neck portion or the envelope to absorb substantially ali of said mercury, and subsequently vaporizing said magnesium and mercury and causing said magnesium to deposit substantially solely on said neck portion of the envelope and to absorb substantially all of the mercury.

d. An electric lamp embodying an envelope containing electron emitting electrodes of the heated type and containing at least one rare gas, and a getter deposit mainly on a part of the wall of the envelope remote from the electrodes and containing mercury which is vaporizable from the getter deposit by the heat produced by the operation of the lamp and is in a sufiiciently small quantity to be substantially completely reabsorbable by the getter deposit upon cooling after operation of the lamp is stopped, said gas and mercury vapor both being excitable to luminescence by said electrodes.

5. An electric illuminating lamp embodying an envelope containing a rare gas filling excitable to luminescence by cooperating electrodes at least one of which is adapted to be heated to electron emission temperature, said envelope containing a vaporizable substantially opaque getter deposited mainly on a part of the envelope through which substantially no light is required to be transmitted and having mercury absorbed therein and from which said mercury is vaporizable by the heat of operation of the lamp, said mercury being in a sufiiciently small quantity to be substantially completely reabsorbable by the getter deposit upon cooling of the lamp.

6. An electric illuminating lamp embodying an envelope which is bulb-shaped with a neck portion through which electrode leads enter and contains a, rare gas filling and mercury vapor both excitable to luminescence by cooperating electrodes at least one of which is adapted to be heated to electron emission temperature, said neck mrtion of the envelope having vaporized in it a sumcient quantity of magnesium to absorb substantially all the mercury.

7. An electric illuminating lamp comprising a bulb-shaped envelope having a neck portion containing a re-entrant tube carrying a seal and lead-in wires, cooperating electrodes, a gaseous atmosphere in the envelope excitable to luminescence by said electrodes, and a metal ring located around the re-entrant tube in the neck portion of the envelope for supporting a vaporiz able getter and adapted to be heated by high frequency induction.

8. An electric illuminating lamp comprising an envelope, a gas filling therein consisting at least of neon, cooperating electrodes at least one of which is adapted to be heated indirectly to electron-emitting temperature, a getter in the envelope in which mercury is absorbed and from which it is vaporizable by the heat produced by the operation of the lamp, said mercury being in sufiiciently small quantity when it is vaporized from the getter and it and the gas filling are excited to luminescence by the electrodes to give a substantially white light effect, the mercury is not in operation.

9. An electric illuminating lamp comprising a bulb-shaped envelope with a neck portion through which lead-in wires pass, a rare gas filling in the envelope consisting of neon and helium, cooperating electrodes in the envelope at least one of which is adapted to be heated indirectly to electron emitting temperature, magnesium deposited in the neck only of the envelope and having mercury absorbed in it and vaporizable therefrom by the heat produced by the operation of the lamp, said mercury being in a sufficiently small quantity when vaporized from the getter and it and the rare gas filling are excited to luminescence by the electrodes to give a substantially white lightefiect. or V or V V V V ANTON LEDERER. 

